Abstract: An endoprosthetic elbow joint device has a humeral component in the form of two like frusto-cones coaxially connected at their narrow ends and with their wider ends mutually convergently inclined to wedge into the intracondylar notch in the humerus when resected. This component is secured with cement, the component end faces being provided with a relieved structure of grooves or ribs extending in the relevant directions of inclination. The device also has an ulnar component of less than semi-circular toroidal form with its radially inner face complementary to and engaged with the above double cone. Again cement fixation is used in the ulna with a suitable relieved structure to key the component. Preferably this structure includes a chordally-directed groove to allow passage of a bone screw longitudinally through the olecranon so that the latter can be detached to expose the implantation site and thereafter reattached.

Abstract: An endoprosthetic knee joint device with separate pairs of femoral and tibial condylar runner and track components is improved in respect of bone cement fixation surfaces, mutually articulatory bearing surfaces, and securement location relative to each other and the relevant bones. The femoral components have L-shaped fixation surfaces defining a slightly obtuse angle, and the tibial component fixation surfaces are tapered. The femoral component bearing surfaces have longitudinal convex curvature of higher and lower order over respective end portions, the tibial component bearing surface has longitudinal concave curvature of lowest order, and these bearing surfaces have complementary lateral curvatures of highest order. All components have recesses at one end to engage a jig assembly which connects with the femur in predetermined relationship and locates the components relative to the natural condyles.